OFFSET
1,1
COMMENTS
Digit 0 is not allowed. - Robert Israel, Sep 14 2020
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
181 is a member as replacing 1 by 10-1 = 9 and 8 by 10-8 =2 gives 929 which is also a prime.
MAPLE
R:= NULL: count:= 0:
for d from 1 by 2 while count < 100 do
m:= ceil(d/2);
for r from 0 to 9^m-1 do
L:= convert(9^m+r, base, 9)[1..m] + [1$m];
L:= [ seq(L[-i], i=1..m-1), op(L)];
x:= add(L[i]*10^(i-1), i=1..d);
if isprime(x) and isprime((10^d-1)*10/9-x) then R:= R, x; count:= count+1
fi
od od:
R; # Robert Israel, Sep 14 2020
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Sep 23 2003
EXTENSIONS
Corrected and extended by David Wasserman, Jul 18 2005
STATUS
approved